Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.awt.*;
import java.io.*;
import java.util.*;

public class Abc {
    public static void main(String[] args) throws Exception {
        FastReader sc = new FastReader();
        int n=sc.nextInt(),m=sc.nextInt();
        int arr[][]=new int[n][m];
        for (int i=0;i<n;i++){
            for (int j=0;j<m;j++){
                arr[i][j]=sc.nextInt();
            }
        }
        int min=Integer.MAX_VALUE;
        int ans=-1;
        for (int k=0;k<=500;k++){
            int tmp[][]=new int[n][m];
            for (int i=0;i<n;i++){
                for (int j=0;j<m;j++)tmp[i][j]=arr[i][j];
            }
            int c=k;
            boolean f=true;
            for (int j=0;j<m;j++){
                tmp[0][j]-=k;
                if (tmp[0][j]<0){
                    f=false;
                    break;
                }
            }
            if (!f)continue;
//            if (k==1) {
//                for (int i = 0; i < n; i++) {
//                    for (int j = 0; j < m; j++) {
//                        System.out.print(tmp[i][j] + " ");
//                    }
//                    System.out.println();
//                }
//            }
            for (int j=0;j<m;j++) {
                int x=tmp[0][j];
                for (int i = 0; i < n; i++) {
                    tmp[i][j]-=x;
                    if (tmp[i][j]<0){
                        f=false;
                        break;
                    }
                }
                c+=x;
            }
            if (!f)continue;
//            if (k==1) {
//                for (int i = 0; i < n; i++) {
//                    for (int j = 0; j < m; j++) {
//                        System.out.print(tmp[i][j] + " ");
//                    }
//                    System.out.println();
//                }
//            }
            for (int i=1;i<n;i++){
                int x=tmp[i][0];
                for (int j=0;j<m;j++){
                    tmp[i][j]-=x;
                    if (tmp[i][j]<0){
                        f=false;
                        break;
                    }
                }
                c+=x;
            }
            if (!f)continue;
//            if (k==1) {
//                for (int i = 0; i < n; i++) {
//                    for (int j = 0; j < m; j++) {
//                        System.out.print(tmp[i][j] + " ");
//                    }
//                    System.out.println();
//                }
//            }
            if (isValid(tmp)){
                if (c<min){
                    min=c;
                    ans=k;
                }
            }
        }
        if (min==Integer.MAX_VALUE) System.out.println(-1);
        else {
            StringBuilder sb=new StringBuilder();
            sb.append(min+"\n");
            int k=ans;
            int tmp[][]=arr.clone();
            for (int j=0;j<m;j++){
                tmp[0][j]-=k;
            }
            for (int i=0;i<k;i++){
                sb.append("row "+(1)+"\n");
            }
            for (int j=0;j<m;j++) {
                int x=tmp[0][j];
                for (int i = 0; i < n; i++) {
                    tmp[i][j]-=x;
                }
                for (int l=0;l<x;l++){
                    sb.append("col "+(j+1)+"\n");
                }
            }
            for (int i=1;i<n;i++){
                int x=tmp[i][0];
                for (int j=0;j<m;j++){
                    tmp[i][j]-=x;
                }
                for (int l=0;l<x;l++){
                    sb.append("row "+(i+1)+"\n");
                }
            }
            System.out.print(sb);
        }
    }
    static boolean isValid(int arr[][]){
        for (int i=0;i<arr.length;i++){
            for (int j=0;j<arr[0].length;j++){
                if (arr[i][j]!=0)return false;
            }
        }
        return true;
    }
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader() {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
    }
}